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Remove dshot_telemetry_start_margin setting to use auto-tune(#13075) #13082

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merged 2 commits into from
Sep 20, 2023
Merged

Remove dshot_telemetry_start_margin setting to use auto-tune(#13075) #13082

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9d0cbd1
Remove dshot_telemetry_start_margin setting and auto-tune instead (#1…
SteveCEvans Sep 18, 2023
5a5e0ba
Fix define
haslinghuis Sep 20, 2023
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1 change: 0 additions & 1 deletion src/main/cli/settings.c
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Original file line number Diff line number Diff line change
Expand Up @@ -847,7 +847,6 @@ const clivalue_t valueTable[] = {
#ifdef USE_DSHOT_BITBANG
{ "dshot_bitbang", VAR_UINT8 | HARDWARE_VALUE | MODE_LOOKUP, .config.lookup = { TABLE_OFF_ON_AUTO }, PG_MOTOR_CONFIG, offsetof(motorConfig_t, dev.useDshotBitbang) },
{ "dshot_bitbang_timer", VAR_UINT8 | HARDWARE_VALUE | MODE_LOOKUP, .config.lookup = { TABLE_DSHOT_BITBANGED_TIMER }, PG_MOTOR_CONFIG, offsetof(motorConfig_t, dev.useDshotBitbangedTimer) },
{ "dshot_telemetry_start_margin", VAR_UINT8 | HARDWARE_VALUE , .config.minmaxUnsigned = { 0, 100 }, PG_MOTOR_CONFIG, offsetof(motorConfig_t, dev.telemetryStartMargin) },
#endif
#endif
{ PARAM_NAME_USE_UNSYNCED_PWM, VAR_UINT8 | MASTER_VALUE | MODE_LOOKUP, .config.lookup = { TABLE_OFF_ON }, PG_MOTOR_CONFIG, offsetof(motorConfig_t, dev.useUnsyncedPwm) },
Expand Down
113 changes: 79 additions & 34 deletions src/main/drivers/dshot_bitbang_decode.c
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Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,7 @@
#include "build/debug.h"
#include "drivers/dshot.h"
#include "drivers/dshot_bitbang_decode.h"
#include "drivers/time.h"

#define MIN_VALID_BBSAMPLES ((21 - 2) * 3)
#define MAX_VALID_BBSAMPLES ((21 + 2) * 3)
Expand All @@ -49,6 +50,15 @@ uint16_t bbBuffer[134];
#define BITBAND_SRAM_BASE 0x22000000
#define BITBAND_SRAM(a,b) ((BITBAND_SRAM_BASE + (((a)-BITBAND_SRAM_REF)<<5) + ((b)<<2))) // Convert SRAM address

// Period at which to check preamble length
#define MARGIN_CHECK_INTERVAL_US 500000

// Target 5 clock cycles of input data ahead of leading edge
#define DSHOT_TELEMETRY_START_MARGIN 5

static uint32_t minMargin = UINT32_MAX;
static timeUs_t nextMarginCheckUs = 0;

static uint8_t preambleSkip = 0;

typedef struct bitBandWord_s {
Expand Down Expand Up @@ -102,11 +112,10 @@ static uint32_t decode_bb_value(uint32_t value, uint16_t buffer[], uint32_t coun
return value;
}


#ifdef USE_DSHOT_BITBAND
uint32_t decode_bb_bitband( uint16_t buffer[], uint32_t count, uint32_t bit)
{
uint8_t startMargin;

timeUs_t now = micros();
#ifdef DEBUG_BBDECODE
memset(sequence, 0, sizeof(sequence));
sequenceIndex = 0;
Expand All @@ -120,6 +129,8 @@ uint32_t decode_bb_bitband( uint16_t buffer[], uint32_t count, uint32_t bit)
// Jump forward in the buffer to just before where we anticipate the first zero
p += preambleSkip;

DEBUG_SET(DEBUG_DSHOT_TELEMETRY_COUNTS, 3, preambleSkip);

// Eliminate leading high signal level by looking for first zero bit in data stream.
// Manual loop unrolling and branch hinting to produce faster code.
while (p < endP) {
Expand All @@ -131,13 +142,16 @@ uint32_t decode_bb_bitband( uint16_t buffer[], uint32_t count, uint32_t bit)
}
}

startMargin = p - b;
DEBUG_SET(DEBUG_DSHOT_TELEMETRY_COUNTS, 3, startMargin);
const uint32_t startMargin = p - b;

if (p >= endP) {
// not returning telemetry is ok if the esc cpu is
// overburdened. in that case no edge will be found and
// BB_NOEDGE indicates the condition to caller
if (preambleSkip > 0) {
// Increase the start margin
preambleSkip--;
}
return DSHOT_TELEMETRY_NOEDGE;
}

Expand Down Expand Up @@ -203,6 +217,7 @@ uint32_t decode_bb_bitband( uint16_t buffer[], uint32_t count, uint32_t bit)
}
}

// length of last sequence has to be inferred since the last bit with inverted dshot is high
if (bits < 18) {
return DSHOT_TELEMETRY_NOEDGE;
}
Expand All @@ -213,20 +228,34 @@ uint32_t decode_bb_bitband( uint16_t buffer[], uint32_t count, uint32_t bit)
return DSHOT_TELEMETRY_NOEDGE;
}

// Data appears valid
if (startMargin < minMargin) {
minMargin = startMargin;
}

if (cmpTimeUs(now, nextMarginCheckUs) >= 0) {
nextMarginCheckUs += MARGIN_CHECK_INTERVAL_US;

// Handle a skipped check
if (nextMarginCheckUs < now) {
nextMarginCheckUs = now + DSHOT_TELEMETRY_START_MARGIN;
}

if (minMargin > DSHOT_TELEMETRY_START_MARGIN) {
preambleSkip = minMargin - DSHOT_TELEMETRY_START_MARGIN;
} else {
preambleSkip = 0;
}

minMargin = UINT32_MAX;
}

#ifdef DEBUG_BBDECODE
sequence[sequenceIndex] = sequence[sequenceIndex] + (nlen) * 3;
sequenceIndex++;
#endif

// The anticipated edges were observed

// Attempt to skip the preamble ahead of the telemetry to save CPU
if (startMargin > motorConfig()->dev.telemetryStartMargin) {
preambleSkip = startMargin - motorConfig()->dev.telemetryStartMargin;
} else {
preambleSkip = 0;
}

if (nlen > 0) {
value <<= nlen;
value |= 1 << (nlen - 1);
Expand All @@ -235,10 +264,11 @@ uint32_t decode_bb_bitband( uint16_t buffer[], uint32_t count, uint32_t bit)
return decode_bb_value(value, buffer, count, bit);
}

#else // USE_DSHOT_BITBAND

FAST_CODE uint32_t decode_bb( uint16_t buffer[], uint32_t count, uint32_t bit)
{
uint8_t startMargin;

timeUs_t now = micros();
#ifdef DEBUG_BBDECODE
memset(sequence, 0, sizeof(sequence));
sequenceIndex = 0;
Expand All @@ -259,6 +289,8 @@ FAST_CODE uint32_t decode_bb( uint16_t buffer[], uint32_t count, uint32_t bit)
// Jump forward in the buffer to just before where we anticipate the first zero
p += preambleSkip;

DEBUG_SET(DEBUG_DSHOT_TELEMETRY_COUNTS, 3, preambleSkip);

// Eliminate leading high signal level by looking for first zero bit in data stream.
// Manual loop unrolling and branch hinting to produce faster code.
while (p < endP) {
Expand All @@ -269,16 +301,17 @@ FAST_CODE uint32_t decode_bb( uint16_t buffer[], uint32_t count, uint32_t bit)
break;
}
}

startMargin = p - buffer;
DEBUG_SET(DEBUG_DSHOT_TELEMETRY_COUNTS, 3, startMargin);
const uint32_t startMargin = p - buffer;

if (p >= endP) {
// not returning telemetry is ok if the esc cpu is
// overburdened. in that case no edge will be found and
// BB_NOEDGE indicates the condition to caller
// Increase the start margin
preambleSkip--;
if (preambleSkip > 0) {
// Increase the start margin
preambleSkip--;
}
return DSHOT_TELEMETRY_NOEDGE;
}

Expand Down Expand Up @@ -317,38 +350,50 @@ FAST_CODE uint32_t decode_bb( uint16_t buffer[], uint32_t count, uint32_t bit)

// length of last sequence has to be inferred since the last bit with inverted dshot is high
if (bits < 18) {
// Increase the start margin
preambleSkip--;
return DSHOT_TELEMETRY_NOEDGE;
}

// length of last sequence has to be inferred since the last bit with inverted dshot is high
const int nlen = 21 - bits;
#ifdef DEBUG_BBDECODE
sequence[sequenceIndex] = sequence[sequenceIndex] + (nlen) * 3;
sequenceIndex++;
#endif

if (nlen < 0) {
// Increase the start margin
preambleSkip--;
return DSHOT_TELEMETRY_NOEDGE;
}

// The anticipated edges were observed
// Data appears valid
if (startMargin < minMargin) {
minMargin = startMargin;
}

// Attempt to skip the preamble ahead of the telemetry to save CPU
if (startMargin > motorConfig()->dev.telemetryStartMargin) {
preambleSkip = startMargin - motorConfig()->dev.telemetryStartMargin;
} else {
preambleSkip = 0;
if (cmpTimeUs(now, nextMarginCheckUs) >= 0) {
nextMarginCheckUs += MARGIN_CHECK_INTERVAL_US;

// Handle a skipped check
if (nextMarginCheckUs < now) {
nextMarginCheckUs = now + DSHOT_TELEMETRY_START_MARGIN;
}

if (minMargin > DSHOT_TELEMETRY_START_MARGIN) {
preambleSkip = minMargin - DSHOT_TELEMETRY_START_MARGIN;
} else {
preambleSkip = 0;
}

minMargin = UINT32_MAX;
}

#ifdef DEBUG_BBDECODE
sequence[sequenceIndex] = sequence[sequenceIndex] + (nlen) * 3;
sequenceIndex++;
#endif

// The anticipated edges were observed
if (nlen > 0) {
value <<= nlen;
value |= 1 << (nlen - 1);
}

return decode_bb_value(value, buffer, count, bit);
}
#endif // USE_DSHOT_BITBAND

#endif
10 changes: 5 additions & 5 deletions src/main/drivers/dshot_bitbang_decode.h
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Expand Up @@ -18,14 +18,14 @@
* If not, see <http://www.gnu.org/licenses/>.
*/


#include "platform.h"

#if defined(USE_DSHOT) && defined(USE_DSHOT_TELEMETRY)



uint32_t decode_bb(uint16_t buffer[], uint32_t count, uint32_t mask);
#ifdef USE_DSHOT_BITBAND
uint32_t decode_bb_bitband( uint16_t buffer[], uint32_t count, uint32_t bit);

#else
uint32_t decode_bb(uint16_t buffer[], uint32_t count, uint32_t mask);
#endif

#endif
5 changes: 0 additions & 5 deletions src/main/pg/motor.c
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Expand Up @@ -45,10 +45,6 @@
#define DEFAULT_DSHOT_BURST DSHOT_DMAR_OFF
#endif

#if !defined(DSHOT_TELEMETRY_START_MARGIN)
#define DSHOT_TELEMETRY_START_MARGIN 10
#endif

PG_REGISTER_WITH_RESET_FN(motorConfig_t, motorConfig, PG_MOTOR_CONFIG, 2);

void pgResetFn_motorConfig(motorConfig_t *motorConfig)
Expand Down Expand Up @@ -97,7 +93,6 @@ void pgResetFn_motorConfig(motorConfig_t *motorConfig)
#ifdef USE_DSHOT_BITBANG
motorConfig->dev.useDshotBitbang = DSHOT_BITBANG_DEFAULT;
motorConfig->dev.useDshotBitbangedTimer = DSHOT_BITBANGED_TIMER_DEFAULT;
motorConfig->dev.telemetryStartMargin = DSHOT_TELEMETRY_START_MARGIN;
#endif
}

Expand Down
1 change: 0 additions & 1 deletion src/main/pg/motor.h
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Expand Up @@ -50,7 +50,6 @@ typedef struct motorDevConfig_s {
uint8_t useDshotBitbang;
uint8_t useDshotBitbangedTimer;
uint8_t motorOutputReordering[MAX_SUPPORTED_MOTORS]; // Reindexing motors for "remap motors" feature in Configurator
uint8_t telemetryStartMargin;
} motorDevConfig_t;

typedef struct motorConfig_s {
Expand Down
2 changes: 2 additions & 0 deletions src/main/target/STM32F405/target.h
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Expand Up @@ -57,6 +57,8 @@
#define USE_I2C
#define I2C_FULL_RECONFIGURABILITY

#define USE_DSHOT_BITBAND

#define USE_BEEPER

#define USE_SPI
Expand Down
2 changes: 2 additions & 0 deletions src/main/target/STM32F411/target.h
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Expand Up @@ -49,6 +49,8 @@
#define USE_I2C
#define I2C_FULL_RECONFIGURABILITY

#define USE_DSHOT_BITBAND

#define USE_BEEPER

#ifdef USE_SDCARD
Expand Down